NEW APPROACHES FOR STABILIZATION OF ATORVASTATIN

Atorvastatin (ATV) is a synthetic lipid-lowering agent that most widely used for the prevention of primary and secondary coronary heart disease. It is an unstable substance sensitive to heat, humidity, low pH of the environment, and light, particularly UV radiation. In this study, different methods were investigated in order to improve the stability of the drug including complexation with hydroxypropyl-cyclodextrin (HP--CD), preparation of solid dispersions with Polyvinylpyrolidone (PVP k-30), and a ternary system of both. The use of an antioxidant and elevatating the pH by the addition of a basic substance, like disodiumhydrogen phosphate (DSHP) were also employed. All the prepared systems showed an improvement in the drug stability. The addition of QRT to ATV resulted in a slight improvement in the stability (k= 7.36 x 10 -3 hr -1 ), while, maximum stability was produced by the ternary system. However, the addition of QRT to the ternary system did not produce a significant improvement in the stability of the drug. Other systems produced moderate effects on the stability of ATV. Arrhenius equation was also applied and the energy of activation for each prepared system was calculated